The current art for catalytic coating of metallic fibers is reported by Cerri, et al. in Chemical Engineering Science Vol. 54 (1999) “Catalytic pre-mixed fibre burners” pages 3599-3608, as depositing LaMnO3 catalyst by spray pyrolysis on sintered FeCrAl fiber media for natural gas catalytic combustion. Also, G. Saracco, et al. in Chemical Engineering Journal Vol. 82 (2001), “Improved-Performance Knitted Fibre Mats as Supports for Pre-mixed Natural Gas Catalytic Combustion” pages 73-85 reports a similar coating technique for catalytic pre-mixed fiber burners. However, the adherence of the catalyst to fiber substrate is not good or reliable. It is desirable to have secure adherence of catalysts to substrate and a greatly increased catalytic surface area for increased efficiency.
In addition to the above, the formation of metallic alloy fibers, such as, FeCrAl and FeCrAlY are reported in U.S. Pat. No. 5,205,731 with no mention or suggestion that creating whiskers on the alloy fibers would be beneficial. Use of nested FeCrAl and FeCrAlY fibers in gas combustion systems are also reported in European Patent Appl. 0,157,432 to BV Maatschappij, et al., which also does not mention forming whiskers on the surface of alloy fibers as beneficial. To the contrary, surface modification of Fe—Cr—Al—Y that result in intensive whisker formation, due to fast growing meta-stable phases such as gamma or theta alumina, characteristics of aluminum outward growth is known to rapidly deplete aluminum and greatly reduce the lifetime of FeCrAl metal alloy fibers.
None of the prior art references use a process for forming whiskers on a metallic alloy fiber. Also, none of the prior art references deposit a catalyst layer on whiskers formed on a FeCrAl metal alloy fiber surface. Thus, the novel products of the present invention meet a commercial need for products and systems useful in technical, medical and pharmaceutical applications, such as, cleaning exhaust gases in power plants, in petrochemical and chemical plants, in automobile catalytic converters, filtration systems using particulate filters, polymer filtration, catalyst recovery burners, industrial gas filtration, liquid filtration, catalyst and implant supports, and the like.